Οn August 31 the Greek Orthodox Church commemorates The Placing of the Cincture or Belt (Sash) of the Most Holy Mother of God. Before this, the holy relic, entrusted to the Apostle Thomas by the Mother of God Herself, was kept by pious Christians at Jerusalem after Her Dormition.
The event is honored by the Greek Orthodox Church on the last day of August, which is the month dedicated to Panagia.
The Placing of the Venerable Belt of the Most Holy Theotokos in a church of Constantinople’s Chalcoprateia district took place during the reign of the emperor Theodosius the Younger. Before this the holy relic, entrusted to the Apostle Thomas by the Mother of God Herself, was kept by pious Christians at Jerusalem after Her Dormition. During the reign of Emperor Leo the Wise (886-911), his wife Zoe was afflicted with an unclean spirit, and he prayed that God would heal her.
The empress had a vision that she would be healed of her infirmity if the Belt of the Mother of God were placed upon her. The emperor then asked the Patriarch to open the coffer. The Patriarch removed the seal and opened the coffer in which the relic was kept, and the Belt of the Mother of God appeared completely whole and undamaged by time. The Patriarch placed the Belt on the sick empress, and immediately she was freed from her infirmity. They sang hymns of thanksgiving to the Most Holy Theotokos, then they placed the venerable Belt back into the coffer and resealed it.
In commemoration of the miraculous occurrence and the twofold Placing of the venerable Belt, the Feast of the Placing of the Venerable Belt of the Most Holy Theotokos was established. Parts of the holy Belt are in the Vatopedi monastery on Mt. Athos, in Trier monastery, and in Georgia.
Sources: oca.org and greekcitytimes.com